Thank you for your comment!
Most of the design choices were made for multiplayer 1v1 in mind. The control buttons were made group together on the keyboard, so that 2 players can easily share 1 keyboard and the 4 minute timer is there to push the players to polish their runs in a set amount of time, making it a compatitive experience.
The tracks are actually randomly generated. That's why didn't include a best overall time and that's why the timer doesn't let you play on one track indefinitely. For solo-play, a future idea is to get the seed of the randomly generated track to share it to your friends, so that you can race with them on different devices together. Then the 4 minute timer will have more sense.